Counterbalanced crankshaft for internal-combustion engines



Sept. 18, 1951 J. E. WlTZKY ET AL 2,568,576

COUNTERBALANCED 'CRANKSHAFT FOR INTERNAL-COMBUSTION ENGINES Filed June 30, 1947 2 Sheets-Sheet l @Iwucnfow JULIUS E.WITZKY WOLFGA N6 3 LANG RICHARD .1. K08

Sept. 18, 1951 J. E. WlTZKY ET AL 2,568,576

COUNTERBALANCED CRANKSHAFT FOR INTERNAL-COMBUSTION ENGINES Filed June 30, 1947 2 Sheets-Sheet 2 gnwcufom JULIUS E.WITZKY WOLFGANG S. LANG RICHARD J. KOB

Patented Sept. 18, 1951 COUNTERBALANCED CRANKSHAFT FOR INTERNAL-COIHBUSTION ENGINES Julius E. Witzky, Stuttgart-Cannstatt, and. Wolf gang S. Lang and Richard J. Jakob, Wendi- ]ingen-Neckar, Germany, assignors to; the; United States of America as represented by-the- Secretary, of War Application June 30, 1947, Serial No. 758,034

4 Claims. 1

This invention relates to crankshafts for internal combustion engines, and more particularly to counterweighted crankshafts to obtain the proper operating balance.

One of the objects ofthe invention is to provide an improved counterweight construction of internal combustion engines. Another object of the invention i to provide a new and improved method of attaching counterweights to crankshafts, which will insurerigidity and permanency to the connection.

Another object of the invention is to provide an elliptically shaped cheek on, a crankshaft which is somewhat enlarged to obtain a shoulder, thereby eliminating use ofea lobe normally provided on a conventional crankshaft cheek, thus simplifying the forging thereof.

Another object of the invention is to provide counterweights for crankshafts, which may be forged independently or cut from a flat ring into segments and may be riveted to a cheek provided on the crankshaft.

Engines designed to operate at high speed do not permit the fastening of counterweights to crankshafts thereof by simple instrumentalities such as bolts or welding and the required precise fitting for riveting is performed conventionally by expensive milling and fitting operations.

It is therefore another aim and purpose of the invention to provide a method of machining the crankshafts and counterweights, which perm-its the exclusive application of simple and inexpensive turning operations to obtain the necessary precision without fitting operations.

With the above and other objects and advantages in view, the invention consists of certain features. of construction andoperation of parts which willhereinafterbe describedand shown in the accompanying drawings, in which:

Fig. 1 is a cross-sectional end view of a crankshaft, including an elliptically shaped cheek, with a counterweight removed therefrom and illustrating the method of obtaining the necessary precision on the face of the cheek of the crankshaft by the simple turning operation thereof on a lathe for fitting a counterweight thereto;

Fig. 2 is a side elevation thereof;

Fig. 3 is an end view similar to Fig. 1, with the counterweight attached to the crankshaft cheek; and

Fig. 4 is a side elevation of Fig. 3 partly in section.

Referring more specifically to the drawings, there is shown in Figs. 1 and 2 a crankshaft l with the counterweight 2 (illustrated in Figs. 3

2e and 4) removed therefrom; The. crankshaft. I. may be cast, forged orformed: in any other suitable manner and isprovided-t with checks 3 and. 3. carrying an integral crankpin 4; The contour of thecrankshaft'cheek 3 is elliptical. and'shaped: by means of turningon acrankshaft'lathe (not shown) to provide a; circular are. 4 described about the center A of the crankshaft I withany desired radius a as shown in Fig- 1. The-crankshaft cheek. 3 is further turned on a latheito provide a circular are 5 described about the center.

Bof the crankpin or member 4, with any desired radius b. provinding a flange. 6 on the check 3 forming a shoulder. I in the shape of .a.circu1ar: arc. Any suitable number of spacedarcuately aligned holes 8 may be provided in the :fiangeS. of the crankshaft cheek 3 for a purpose which will hereinafter appear. The outer periphery 9 and the inner face H) of the flange 6; together with the periphery l I of the shoulder I is turned on a lathe to the: required precision whereby an. arcuately shaped recess or seat isprovided on the crankshaft cheek defined bytwo intersecting cir-- cular arcs. By providing a shoulder l onzthe crankshaft check 3, no lobe hasto be forged on the crankshaft cheek, thus, simplifying the forge ing operation.

Referring to Figs. 3 and 4, it will be seen that the counterweight 2 is in the form of an arcuate segment readily turned on'a lathe to provide a flange I2 forming a shoulder I3. Theperipheral. face [4 of the counterweight shoulder. I3.may be. turned on a lathe around. the common center A using the same radius a employed for turning the outer peripher 9 of the flange 6 of the crankshaft cheek 3 and the peripheral face 15 of the flange 12 on the counterweight may likewise be. turned on a lathe around the common center B using the same radius 1) employed for turning the peripheral face ll of the crankshaft. shoulder 1 whereby an arcuately shaped recess is provided on the counterweight. The flange l2 of the counterweight 2 is provided with a series of spaced arcuately aligned openings 16 adapted to register with the holes 8 in the flange 6 of the crankshaft. Assuming that the peripheral face M of shoulder l3 on the counterweight 2, the peripheral face I5 of the counterweight flange l2 and the inner face I! of the counterweight to have been turned on a lathe to the proper precision, then counterweight 2 may be readily fitted in the recess of crankshaft cheek 3, with the peripheral face I4 of the counterweight shoulder l3 abutting against the peripheral face 9 on the flange 6 of the crankshaft cheek 3, and the face ll of the counterweight flange I2 abutting againstthe face ll] of the crankshaft flange 6. The flange [2 of the counterweight 2 is secured to the flange 6 of the crankshaft l by means of rivets H3 or the like mounted in the aligned holes 8 and the openings I6 formed in the crankshaft flange 6 and the counterweight flange 12, respectively. It is within the purview of the present invention to make counterweight 2 removable for ready replacement, if desired, with a similar or different counterweight of the same configuration. To this end, rivets [8 may be replaced by suitable bolts. By virtue of the a series of such counterweights ma be arrangedin a fixture as segments with a common center and turned on a crankshaft lathe only at their inner faces, or the counterweights may be cut from a fiat ring into segments.

In the light of the above description, it will be seen that the instant invention provides a new and efficient counterweighted crankshaft and method of making the same, which is well adapted for the purpose intended.

Having thus described our invention, what we claim as new and wish to secure by Letters Patcut is:

1. A counterbalanced crankshaft comprising main bearing segments, a throw segment intermediate the bearing segments, a cheek interconnecting each bearing segment with the throw segment, a smooth perforated member in one of the cheeks on a side thereof opposite to the throw segment and remote from the throw segment, a counterweight fixedly mounted on the member, the said counterweight having a smooth surface and perforations complemental to the smooth surface and perforations of the member, the entire mass of the counterweight being located on a side thereof opposite the throw segment at approximately the adjacent main bearing segment, and means connecting the counterweight to the member, the said counterweight and the said cheek forming substantially continuous side surfaces.

2. A counterbalanced crankshaft for an internal combustion engine comprising main bearing segments, throw segments intermediate said main bearing segments, said throw segments comprising cheeks and a crankpin connecting the said cheeks, a smooth perforated member formed adjacent to the juncture of the said main bearing segment and a cheek of the throw segment,

a counterweight having a'smooth perforated area complementary to said smooth perforated mem ber formed at the said juncture of the said main bearing segment and the said cheek of the throw segment, and fastening means fixedly securing the said counterweight to the said member in registering engagement and forming an integral structure having substantially continuous side surfaces, the entire mass of said counterweight beingpositioned opposite the main bearing seg- 'ment on the side opposite the throw segment.

3. A counterbalanced crankshaft for an internal combustion engine comprising a main shaft, main bearing segments disposed along the said mainshaft, cheek segments intermediate said main bearing segments, a crankpin intermediate said cheek segments, a smooth perforated member at the end of the said cheek segment opposite the said crankpin, means for securing a counterweight to said member, a onepiece counterweight including complementary surface and perforations fixedly secured to said smooth perforated member, said cheek segment" and said counterweight forming substantially continuous side surfaces, the entire mass of the;

said counterweight being positioned at a radius from the said main shaft and on a side opposite the said crankpin; 7

4. A counterbalanced crankshaft comprising main bearing segments, cheekfisegments intermediate the bearing segments, a crankpin segment interconnecting the cheek segments; a smooth perforated member in one of the cheeks on a side thereof opposite the crankpin; a counterweight fixedly mounted on the member, the said counterweight having a smooth surface and perforations complementary to the member; the entire mass of the counterweight being located opposite the center of rotation of the crankshaft in relation to thecrankpin, the counterweight and the cheek member forming substantially continuous side surfaces.

JULIUS E. wITzKY. WOLFGANG s. LANG. RICHARD J. JAKOB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

